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Use Multiple Channels for Faster Wireless Networking

icypyr0 writes "The Register reports: 'Current dual-mode 802.11 'a' and 'b' access points use only one of Wi-Fi's 11 RF channels at a time, with users taking turns. The Engim chipset can 'see' all 11 at once, and can use the three non-overlapping ones (1, 6 and 11) in parallel, increasing total throughput and enabling features to be incorporated in silicon that are usually implemented, at extra cost and performance degradation, in software.'"

109 of 298 comments (clear)

  1. Range is fine but... by Cyno01 · · Score: 4, Funny

    Unfortunately the neighbors decided to microwave a burrito and their throughput went all to hell.

    --
    "Sic Semper Tyrannosaurus Rex."
    1. Re:Range is fine but... by swordboy · · Score: 4, Funny

      Unfortunately the neighbors decided to microwave a burrito and their throughput went all to hell.

      Who needs a microwave when you can just stick the burrito in the access point's line-of-sight?

      I suppose that could possibly affect throughput as well...

      --

      Life is the leading cause of death in America.
    2. Re:Range is fine but... by jedrek · · Score: 4, Funny

      Man... I wish we could get microwave burritos here in Poland.

      Mmm... waveolicious.

  2. Polish by Crash42 · · Score: 5, Funny

    Well, my polish is not that good (except my RPN/RPL) so i'll take your word for it....

    --


    ....Excuse me, but ... ah, forget it...
  3. Old joke to be duped by heir2chaos · · Score: 3, Funny

    How many pollocks did it take to acheive this?

  4. Comment removed by account_deleted · · Score: 4, Funny

    Comment removed based on user account deletion

  5. 110 Km? by JRHelgeson · · Score: 2, Funny

    WOW! 110 Kilometers! What is that, like 500 feet?

    --
    Good security is based upon reality and common sense. Common sense is a function of having common knowledge.
    1. Re:110 Km? by grokster · · Score: 2, Funny

      How big are your feet?

    2. Re:110 Km? by dcordeiro · · Score: 2, Informative

      FYI,
      google calculator says its something like:
      110 kilometers = 68.3508311 miles

  6. Err... it is a cheat by arivanov · · Score: 5, Interesting

    Err... My polish is crap, but unless I am mistaken they seem to have used a 500mW aplifier and a 27dbM antenna to boot.

    What's next? Sticking it in the middle of Aresibo and claiming half a light year range?

    --
    Baker's Law: Misery no longer loves company. Nowadays it insists on it
    http://www.sigsegv.cx/
    1. Re:Err... it is a cheat by Zocalo · · Score: 4, Funny
      What's next? Sticking it in the middle of Aresibo and claiming half a light year range?

      Pshaw! Who needs Arecibo? *My* crappy off-the-shelf 802.11b card can get *infinite* range un-aided! True, picking the signal out from the noise at more than 50ft is proving problematic at present, but once I've ironed out that minor problem I'm well on my way to PROFIT!!!

      Or was I the only person paying attention in physics when it was explained how *any* electromagnetic transmission has infinite range, since decaying amplitude in accordance with the inverse square rule never reaches zero? Assuming a perfect vacuum, naturally.

      --
      UNIX? They're not even circumcised! Savages!
  7. Hrmm by acehole · · Score: 4, Funny

    I guess using two pringles cans instead of two really did the trick.

    --
    Be you Admins? nay, we are but lusers!
  8. Damn measurement standards..!! by Anonymous Coward · · Score: 4, Funny

    110kms??? What's that in freight trains?

    or how many of the sears tower layed on it's side?

    1. Re:Damn measurement standards..!! by RabidMonkey · · Score: 2, Interesting

      DAMMIT!

      apparently pressing ctrl-enter submits ... same as how I submit tickets .. stupid habits die hard.

      lets continue that.

      Sears tower = 442m
      so we have 248.8688 sears towers

      Boxcar = 43 feet avg (source)
      Avg freight train length=45 cars (some other site that won't load but is cached)
      Avg lenght in feet = 1935 feet

      google tells me theres 0.3048 metres in a foot so we have the avg freight train being 589.788m long.

      That means we have 186.5077 freight trains (not counting engines) end to end


      length of football field (cdn) = 100m
      length of football field (us) = 109.1m (source

      That leaves us with 1,100 cdn football fields, or 1008.2493 american fields.

      a us dollar bill is 156mm long (source
      so that gives us 705128.2051 dollar bills, end to end

      asian elephants can grow to 340cm (3.4m) (source)
      so thats 32352.9412 elephants

      I think thats good enough for now. back to work.

      --
      We emerge from our mother's womb an unformatted diskette; our culture formats us. - Douglas Coupland
  9. Huzaa! by rf600r · · Score: 2, Funny

    Maybe there's hope for me getting a signal down the hall?

    Naaaahhhhh.......

  10. that's 110 kilometers... by 192939495969798999 · · Score: 5, Informative

    or 66 miles for the math impaired (sigh). Still, that's rad! You could access that across the English channel!

    --
    stuff |
    1. Re:that's 110 kilometers... by zerocool^ · · Score: 4, Insightful

      I don't know about across the english channel. At some point, you pass the horizon, where you can't go any further due to the curvature of the earth. I was pretty sure that level was around ... either 50 or 100 miles, I don't remember. Can you see France from Kent?

      ~Will

      --
      sig?
    2. Re:that's 110 kilometers... by Rosco+P.+Coltrane · · Score: 3, Funny

      You could access that across the English channel!

      Yes, and just imagine the improvement when they finally dig the 802.11b tunnel!

      --
      "A door is what a dog is perpetually on the wrong side of" - Ogden Nash
    3. Re:that's 110 kilometers... by chrestomanci · · Score: 2, Informative
      Can you see France from Kent?

      You can, though it is easier to see Kent from france, as the white cliffs of dover stand out quite well.

      BTW, it is about 20 miles, (across the straights of dover) and there are tall cliffs on both sides, which improves sight lines

    4. Re:that's 110 kilometers... by akadruid · · Score: 3, Informative

      I don't know about across the english channel
      Damn straight you don't!
      Distance will not be a problem - at only 21 miles (34 km) across at the narrowest point, weather permitting, you can clearly see 'Le Francais' from the White Cliffs of Dover.
      you can't go any further due to the curvature of the earth
      WTF? Surely you can't see any further! Actually you're miles out here too.
      The distance (in km) of the horizon on earth, on a plain, is approximately s(13h) where h is the height (in metres) of the eyes multiplied by the 13, and s is the square root symbol slashcode can't cope with.
      Were you to mount an antenna on the beach, you would find that the horizan at around 5km away would be a big problem.
      Stick it up on said White Cliffs of Dover, at 250m above sea level, and you will have no problems with line of sight.
      The only barrier to this idea is the regulations governing the area.
      Sources: Channel, Cliffs, Horizan

      --
      "Those who cast the votes decide nothing; those who count the votes decide everything." (attrib. Joseph Stalin)
    5. Re:that's 110 kilometers... by zindorsky · · Score: 2, Funny
      At some point, you pass the horizon, where you can't go any further due to the curvature of the earth

      The earth is flat, sinner.

      --
      If the geiger counter does not click, the coffee, she is not thick.
    6. Re:that's 110 kilometers... by mgg4 · · Score: 2, Informative

      The distance to the horizon can be calculated using the formula:

      D = 1.17 * sqrt(h)

      where "D" is the Distance to the horizon (in nautical miles); and
      "h" is the height of the observer (or antenna) in feet.

      To find the distance you can communicate over the earth using line-of-sight communications (like 2.4 GHz is), you need to do the DTH (Distance to Horizon) calculations for each antenna, and then add them together. This gives you the total distance.

      To get the required 110 km, you would need two antennas about 650 feet (200 meters) tall.

      --
      -- This space for rent.
  11. Geek factor 9.3 useful factor 1 by obi1one · · Score: 2, Interesting

    (error 1337 destination page /.ed) Is increasing the range of current wireless networking equipment really what is needed. I know i personally am turned off from wireless not because of the lack of range, but the lack of speed. There is certainly some cool factor being able to get that masssive a distance, but I dont see this as making wireless more desirable to anyone.

    1. Re:Geek factor 9.3 useful factor 1 by _avs_007 · · Score: 3, Interesting

      I work with a lot of wireless APs and client cards in our lab.

      If you are talking about G type stuff, stay away from Linksys, they have the crappiest range. When I used it in my house, I would get 68db with an Intel 802.11b AP, but the Linksys G router/AP yielded 77db, and that was only going through 2 walls.

      I replaced it with a Netgear WGR614, which uses the Intersil Prism GT chipset (as does the D-Link we tested), and got much better range. Similar to straight B. ~68 or 69 db in my master bedroom.

      In our office environment, the Linsys G would drop signal after walking past the conference rooms. The Netgear G allowed us to almost walk around the entire floor. I connected a signal booster, and found it to be next to worthless, as it did not improve range. If it did, only by 5 ft or so. It still dropped signal as I walked past the conference rooms.

      The measured actual throughput was 4.5mb/s with straight 802.11b, and 21mb/s with the Netgear G.

      Quite suprisingly, I had the best results with the Netgear WAB102 Dualband A/B, which is the only A/B AP that uses Atheros second generation A. Tom's Hardware had a write-up on this. Atheros had a whitepaper. I bought 3 of these, and verified the claims.

      With a Linksys A+G card, (which uses Atheros 5001X+, as does Netgear WAG511), I got slightly weaker signal strength in my master bedroom 70db), but throughput killed both B and G. I was measuring 24mb/sec throughput in non-turbo mode, and 45mb/sec in turbo mode. In the office, I was able to sustain 7-11mb/sec at the opposite end of the building. The Netgear G was only able to sustain 1-2mb/s. Inside the conf rooms, Linksys G had no signal, Netgear G sustained 7mb/sec, Netgear A in turbo mode sustained 24mb/sec.

      In the office, the range of this second generation A actually exceeded that of B, which is something Atheros pointed out in their whitepaper. They said while true A can't go through walls as well as B, the 1st generation A was not performing up to its capabilities. Kind of like how Shannon's law states what is the maximum amount of data that can be carried across wireless, but current technology does not even begin to approach this limit.

      I've tested various client cards from Orinoco, to Cisco Aeronet, Prism 2 and Prism 3 cards, and various Atheros based cards. I that the AP affected range more often than the client cards. Though I have found that anything based on the Atmel chipset to be crap. The USB 802.11 card from Linksys (V2.6) uses this chipset. Unfortunately, the Netgear WAB102, uses Atmel for its B, so its B is crap as well. I just use the A portion of it anyways. But the new Netgear triband router, I beleive uses Atheros for all three bands, it just costs an arm and a leg.

      The Linksys Triband AP, only uses Atheros for the A, it uses Broadcom for B and G, so its G sucks just like the Linksys B/G stuff.

      Somewhere I also read that Linksys will not support any turbo modes in their AP/Routers. (though their A+G client card still supports turbo). Both Atheros and Intersil have planned turbo features. Atheros already had 108mb/s A support in turbo, allowing 45mb/sec throughput by using multiple channels. They already have support for hardware compression, so are promissing a future firmware update that will flip this on, that will allow a turbo mode to sustain 90mb/sec throughput. Its called SuperA. They just released SuperG, which uses multiple B/G channels and compression, to allow 108mb/sec, and I think 45-60mb/sec throughput.

      Intersil's turbo technology is called Nitro. Similar (but incompatible) with Atheros's technology.

  12. They stole his idea... by tbase · · Score: 2, Informative

    Hey - that antenna they're using looks a lot like the one from this story. Of course, he only claims a LOS range of 10 Miles.

    --

    666-607: 6th floor apartment of the beast
  13. Faraway, But So Close? by ausoleil · · Score: 5, Funny

    I for one find it ironic that someone can detect and possibly decode my WiFi signal from roughly 70 miles (per the new world WiFi record) but I can't get a useable signal on my laptop three rooms away from the WAP.

  14. First time I've seen this happen... by JRHelgeson · · Score: 2, Informative
    We /. the site, and it's not even in english. Who's going to RTFA when it's in polish?

    Anyone got a Polish->English translator?

    I checked Google, Babblefish & Dictionary.com with no luck.

    --
    Good security is based upon reality and common sense. Common sense is a function of having common knowledge.
    1. Re:First time I've seen this happen... by Sherloqq · · Score: 2, Informative

      see "Some details" further down.
      I didn't translate, but I summarized the most important bits.

      Here's the equipment they used (which I didn't include in my other post):

      # Antennae - Interline PARABOLIC maxi, 27 dBi
      # Access Points - INTEL Pro/Wireless 2011 Access Point, made by SYBMOL
      # Cables and connectors - BELDEN H-1000, H-155, RG-316, VITELEC connectors
      # Wireless cards - Lucent ORiNOCO PC Card Silver/chipset Agere, ZCom XI-300/chipset Intersil
      # Amplifier - 2.4 GHz, 500 mW

      --
      Have EVDO, will travel.
  15. For those who don't understand Polish by miodekk · · Score: 4, Informative
    The folks used devices that are freely available on the market (WiFi or WLAN PCMCIA cards, amplifier, antennas, etc), chosen locations within the range of about 66 miles (110 km) with visibility (to achieve this you must see the other point).
    So this is a relatively cheap method to get Internet access in distant locations, specifically in mountains, where it is difficult to get a wire.

    Regards

  16. Some details... by Sherloqq · · Score: 5, Informative

    The article claims the experiment used off-the-shelf, commercially available, unmodified components (1.1m / 3.5ft parabolic antenna and a 500mW amplifier). Experiment was conducted in a mountainous region in southwestern Poland.

    So this isn't all that bad... considering the average laptop wireless card puts out, what, 20mW? 50mW? using a 500mW amp to achieve a much greater distance is pretty sweet. By comparison, the article quotes a Swedish experiment which used stratospheric baloons and a 6W amp, but they don't mention the distance achieved.

    Mind you, rules about how much power certain appliances / transmitters can put out with or without a permit vary across the globe, and I'm not sure whether 500mW is legal for private unlicensed use in Poland or not. But if it is, more power to them.

    Now, where can I get mine?? :)

    --
    Have EVDO, will travel.
    1. Re:Some details... by Sherloqq · · Score: 4, Informative

      Few more notes...

      Initially they didn't use an amp, and were getting 20% thruput, which allowed for a 1Mbps link to be established. That link kept going down every few seconds, tho, so they put in the amp. This boosted their RSS readings from 8 to 28, which meant 80% thruput. Having reached that, they tried to ftp a file and although they don't say how big it was, it was copied over at 40kBps, or around 0.5Mbps.

      I don't know about you, but seeing ping replies in the single digits and low teens while ~70miles away makes my spine tingle.

      --
      Have EVDO, will travel.
  17. 110kms? The world record is already 310km. by wherley · · Score: 4, Informative

    Here
    is the story from July of an outfit getting 310km using WiFi from ground to a balloon. This was done by Alvarion and the Swedish Space Corporation and acknowledged by Guinness (as in world records not as in beer).

    1. Re:110kms? The world record is already 310km. by MikeHunt69 · · Score: 3, Interesting
      acknowledged by Guinness (as in world records not as in beer).


      The are actually the same company. (seriously)

  18. Satellite dishes by Rosco+P.+Coltrane · · Score: 5, Funny

    Good thing they did that in Poland. If they had tried this in the US, they'd have been sued by DirecTV for hacking a satellite TV system and the RIAA for trying to set up a P2P link. Of course, none of this would matter since they'd all be in a 3x2 federal pen cell awaiting for months to be charged with setting up a data link that could be used for terrorism ...

    --
    "A door is what a dog is perpetually on the wrong side of" - Ogden Nash
  19. Amateur radio operators do more than this... by josecanuc · · Score: 3, Informative

    105 km is a good ways off. But Amateur Radio operators have been getting better than this with their voice transmissions (and possibly digital) on frequencies from 50 MHz to 10 GHz at the 2003 September VHF QSO Party.

    See some of their setups at http://www.arrl.org/contests/soapbox/?con_id=53.

    Our university station was making contacts on frequencies greater than 2.4 GHz for distances longer than 200 miles. Contrary to common sense, Line-of-Sight is not necessarily required to get microwave transmissions to work over long distances. But they're very weak ;-)

  20. ground attenuation... by AmigaAvenger · · Score: 2, Informative

    The article already is almost dead... Can't check how they did it, BUT... the biggest problem isn't signal power, that part is easy with even a minimal amp and decent parabolic grid antenna. The tough part is the curvature of the earth. Beyond 10 miles or so, you have to get your antennas substantially off the ground, otherwise the amps and high gain antennas make absolutely no difference...

    1. Re:ground attenuation... by Kvasio · · Score: 2, Informative

      According to the page, one of the antenas was on the roof of 10-storey building in Wroc?aw
      (city is located in between 100 and 148 meters above sea level), and (as I believe - it's /.'ed now) the Sniezka mountain (which is 1602 meters above the sea level). Thus the antenas were substantially off the ground...

    2. Re:ground attenuation... by LucidityZero · · Score: 2, Funny
      The tough part is the curvature of the earth.

      Silly! That's why the expirement was done in Poland! The Earth is still flat out there!

      --
      Sig.i>
  21. Re:Wow 110 kilometers by Inflatable+Hippo · · Score: 2, Funny

    > I wonder how many pringles cans that took.

    275,000

    They connected them end to end in an unbroken chain between the base station and client.

  22. If we continue to see developments such as this... by SwansonMarpalum · · Score: 2, Interesting

    It will only mean that last mile solutions will become more plausible for those who don't live within a couple miles of their CO. This is a Good Thing, as having Dial-Up and Satellite as your only options is pretty unbearable.

    --
    "Give away the stone, let the oceans take and transmutate this cold and faded anchor." - Maynard James Keenan
  23. Re:Wow 110 kilometers by Inflatable+Hippo · · Score: 2, Funny

    > I know you're joking, but assuming that a
    > pringles can is 9.25in tall (the best figure I
    > could find), it would take 450,082 end to end
    > to reach that distance. :)

    Pringles cans are bigger when measured in cm.

  24. Oops by Trak · · Score: 3, Funny

    You also meant "Oops"

    It's going to be one of those days, eh?

  25. my personal best: 21.7 miles with 802.11b by puzzled · · Score: 4, Informative


    I did a 21.7 mile shot using Cisco Aironet BR342, Andrew 19dB solid dishes, and YDI
    500 mw amps.

    I'm a bit embarrased to admit using a wireless LAN product for backhaul work, but some morons overtightened
    the patch cable on an Andrew P2F 5.2-5.8 GHz 2' dish hooked to a WiLan AWE-120 5.8 GHz radio and put their link out
    of service.

    Despite extensive tweaking the link never managed more than analog modem speeds. It helped in recomissioning the UNI band stuff, but was otherwise
    useless for hauling traffic.

    802.11[bag] is NOT an access product. Take a look at Alvarion's Breeze Access II, or better yet just wait for an
    802.16 product meant to do access work.

    802.11[bag] is NOT a mobile access product. That market belongs to licensed band products with ISDN like performance offered by cellular companies.
    Anecdotal evidence of mobile access to one police department in a town of 12,000 does not equal proof of concept for operation in urban areas; its plain
    dumb luck coupled with no competing ISM band ISP(yet).

    802.11[bag] is NOT a backhaul product. Backhaul radios are made by WiLan, Redline, Aperto, Proxim, and others. The minimum cost is $2,500 an end just for
    the radio, most of them are in the UNI band, the full duplex products are generally split band 5.2/5.7 GHz, and they provide typically eight to ten
    mbits for entry level products, unlike 802.11b which NEVER, EVER gets 11 mbits in long shots, with 1 or 2 mbits being the typical rate.

    802.11[bag] SHOULD NOT BE DEPLOYED BY MONKEYS. Are you a MoNkEy? If you haven't read Matthew S. Gast's 802.11 book published by OReilly and you
    don't fully grok the implications of the shared MAC layer, you are just throwing nuts and filth from the treetops into the already busy ISM band.

    Slashdot's coverage of other topics is relatively even. The coverage of radio is focused on 802.11[bag] and this is quite laughable most of the time
    to those of us who have actually owned and operated a wireless ISP. Personally I think the editors ought to be giving us a whole lot more information
    on ICOM's D-STAR, a 23cm (1.2 GHz) amateur band voice/data system.

    --
    I am very easy to get along with, but I don't have time to waste being nice to people who are being stupid. -Theo
  26. Re:and probably not legal by div_2n · · Score: 4, Informative

    Actually you can't use a 24db antenna with a 100mw card. The maximum EIRP allowed under the FCC for point to point is 8 watts (39db) and 4 watts for point to multipoint. If you use 100mw (20db) input into a 24db gain antenna, your total EIRP will be 44db or 25 watts. Not legal at all. Also not healthy to stand in front of the antenna for more than a few minutes.

  27. Re:Any ideas by mustangsal66 · · Score: 2, Interesting

    If you have a big fat wallet. Looking either Breezenet gear ($1000 US per radio) which freq hops for security but at 3MB transfer.

    For only around $10K, you can get Tsunami gear 100Mb PTP. It runs 5.4Ghz, just don't stand infront of it.

    Wirless side note. I work with last mile wireless gear. It's cool, but also on our tower is XMRadio. These fookers run at 2.478 (Yeah they don't bother to tune their antenas much). Do the math here... 200Watt radio, 12-14DB gain antenea. Licensed at 200Watts at the antenea. Our spectrum analyzer pulled them in as the stongest signal WITHOUT and antenea. Our RF tech figured out they were running at about 1800Watts at the antenea.

    The good news is there are no birds nests on the tower at all.

    So come on down and have a cookout.

    --
    Why worry? Each of us is wearing an unlicensed "nucular" accelerator on his back.
    Sig changed for readability by G.W.
  28. Translation by Anonymous Coward · · Score: 3, Informative

    Below is my rough, quick and dirty translation of the article. You will have to mach the text to the pictures yourselves. AND it's Polish, not polish. For the difference of meaning see your favourite dictionary.

    ----

    Wi-Fi - World Record - 110 km @ 2.4 GHz

    Two-way DSSS communication in 2.4 GHz band at a distance of 110 km

    INTERLINE company, leading Polish microwave antenna producer, set itself a goal to check possibility of establishing a wireless link in 2.4 GHz band with sequential spectrum spread DSSS (802.11 b standard) at a range currently being only a subject theoretical dispute. The aim of the enterprise was a practical assessment of possibilities and study of phenomenas concerning such a link.

    It should be stressed that the link built is typical ground link and that diversivies it from the one built at the end of 2002 by Swedish company Alvarion and Swedish Space Corporation, which used a stratospheric baloon.

    What is equally important, all elements used in the INTERLINE experiment are off-the-shelf, unmodified equipment available comercially (1.1 meter parabolic antenna and a 500 mW amplifier). Swedish experimentators used 2.4 m parabolic antenna and a 6000 mW amplifier.

    Two localisations were chosen for the link: Wrocaw (a city) and a Hala pod Sniezka (Sniezka is a highiest mountain of Karkonosze), S-W from Jelenia Gora. The distance is around 110 km.

    People
    In the experiment actively participated:
    Piotr Kroplewski - owner of the INTERLINE
    Wiesaw Karpowicz - Manufacturing Manager
    Maciej Kaminski - Technical Division Manager
    Krzysztof Mularczyk - Wireless Network Specialist
    Krzysztof Juszczyszyn - Manufacturing Technologist

    Localisations
    One of a key stages of the experiment was a choice of localisations for stations which were to create a point-to-point link. First of them is a 11 stage house on a one of Wroclaw's districts.
    Second one, key to the experiment, is a glade by the summit of nieka, nerby Dom lski shelter (1400 meters above sea level)

    Equipment
    For the experiment following equipment was chosen:
    Antenas: PARABOLIC maxi, 27 dBi - product of INTERLINE
    Access points: INTEL Pro/wireless 2011 Access Point - made by SYMBOL
    Cables and connectors: cables BELDEN H-1000, H-155, RG-316, connectors VITELEC
    Wireless cards - Lucent ORiNOCO PC Card Silver/chipset Agere, ZCom XI-300/chipset Intersil
    aMPLIFIER - 2.4 GHz, 500 mW

    Of course there were also 2 laptops. Additionally we had: UPS, a set of tools, spare cables, connectors and a gas solder (just in case).

    End-point Wroclaw
    As the date of the experiment was set a time between 12th and 14th of September 2003.

    First stage was mounting and directing an antena in Wroclaw to point towards nieka mountain. Due to good visibility in Wroclaw in the day of installation (2003.09.12), this mountain, which is 1602 meters above sea level, was clearly ivsible. During the directioning vertical angle was important, due to the fact, that the other end of the link was 1400 meters above sea level.

    Installation components
    1. Access Point
    INTEL Pro/Wireless 2011 Access Point + Amplifier 2.4GHz/500 mW
    (here you can read yourself)

    2 Antena cable
    Belden H-1000
    Length: 5 meters
    plugs: type N

    3 Connector
    INTERLINE N/RP-BNC
    Length 30 cm (0.3 m)
    plugs: type N and RP-BNC

    4 ANTENA
    INTERLINE PARABOLIC maxi
    type: directional parabolic antena
    gain: 27 dBi
    radiation angle: 4degrees/6degrees

    Installation - Karkonosze mountains, Kopa-nieka
    On 14th September 2003 all the equipment has been transported with OPEL Frontiera (we had obtained permission of the Karkonosze National Park authorities) to the meadow near the nieka's summit.

    On the installation place weather was as usually in the mountains. Almost all the time the place was covered by clouds. Only from time to time for a dozen seconds wind split the clouds and we were offered splendid views of surrounding mou

  29. Re:and probably not legal by pcjunky · · Score: 2, Informative

    You can run 1 watt into a 6dbi antenna. For point to point you need to reduce your transmitter power 1db for every 3db increase in antenna gain. This means the max antenna gain for 500mw would be 15dbi. Add 9db to the gain to get 24bdi and you need to drop power another 3db or 250mw. 100mw would be legal at 27dbi but not 500mw. Since you need to increase total gain 6dbi every time your double your distance this would make this shot easy with 27dbi antennas and 500mw amps. I have heard of 20 mile links using legal power levals/antennas. The 500mw amps make this easy. To do this legaly would require very high gain antennas perhaps more than 33dbi. This would be the max legal output for 125mw. Most really good radios put out 100mw. I imagine that a 8 foot dish feed with a biquad antenna might do it.

  30. overlap? by StateOfTheUnion · · Score: 3, Insightful

    Are 1,6, and 11 the only channels that don't overlap?

    1. Re:overlap? by LostCluster · · Score: 5, Informative

      All of the channels basically overlap with the other channels. However, if you're on 1, 6, and 11, you manage to cover the entire chart without duplicating yourself.

      Translation: They're covering the entire 2.4 GHz band, and making no appoligies to anybody else who hoped to use it near their systems. Any 2.4 GHz phones will have nowhere to hide.

    2. Re:overlap? by pe1rxq · · Score: 2, Insightful

      You could also use 2, 7 and 12 or 3, 8 and 13 as the spacing would be the same....
      If you really push it you can use smaller spacings such as three or four channels instead of six.

      Jeroen

      --
      Secure messaging: http://quickmsg.vreeken.net/
    3. Re:overlap? by misleb · · Score: 2, Informative

      There is only 1-11 in the US.

      -matthew

      --
      "THERE IS NO JUSTICE, THERE IS ONLY ME." -Death
    4. Re:overlap? by pe1rxq · · Score: 2, Interesting

      Hadn't thought about that...
      We have 1 to 13 here in the Netherlands.
      (Besides its not that hard to use all fourteen)

      Jeroen

      --
      Secure messaging: http://quickmsg.vreeken.net/
    5. Re:overlap? by jerde · · Score: 5, Interesting

      Are 1,6, and 11 the only channels that don't overlap?

      You can get away with using four without much problem. I use 1, 4, 8, 11 for my wide-area 802.11b network.

      You have to plan out in 3 dimensions when you have multiple access points like that. Often the strongest signal available to a roaming user is above or below them, rather than on their floor.

      With only 3 channels available, it's too hard to map them out. With 4 you can at least guarantee that no two adjacent access points are on the same channel.

      - Peter

      --
      INsigNIFICANT
    6. Re:overlap? by StateOfTheUnion · · Score: 2

      Speaking of overlapping channels and consuming large sections of the 2.4 Ghz bandwidth, is there any Ez way to identify what other things may interfere with WiFi on a ceratain channel or channels (e.g. 2.4 Ghz cordless phone, wireless headphones, etc) or is it really just a crapshoot and one has to search for open bandwidth through trial and error?

    7. Re:overlap? by pe1rxq · · Score: 2, Interesting

      Thats what you get with unregulated pieces of spectrum, everyone can put its crap on it....
      You could use a spectrum analyzer to monitor 2.4GHz band to see if anyone in your neighbourhood is using it.

      Jeroen

      --
      Secure messaging: http://quickmsg.vreeken.net/
    8. Re:overlap? by LostCluster · · Score: 2, Informative

      Not really. The 802.11 definiton for the channels are not used by anything else. So, if your 2.4GHz's interface claims there's 20 channels, you just have to guess if those channels are just 1/20th slices of the same pie, or if they've jumped around in their numbering scheme so that one click can get out of the footprint of most problems. You really don't know what your own devices are doing, so how can you predict what the neighbor's are throwing in?

      Trial and error it is...

    9. Re:overlap? by PetWolverine · · Score: 2, Interesting

      With 4 you can at least guarantee that no two adjacent access points are on the same channel.

      Is this a consequence of the four-color theorem? It sounds distantly related.

      --
      I found the meaning of life the other day, but I had write-only access.
    10. Re:overlap? by Grant29 · · Score: 3, Informative

      If you have the Linksys WRT54G, you can use a hacked firmware to get all 14 channels. Check out http://www.sveasoft.com/modules/phpBB2/viewforum.p hp?f=6 for the forums on how people are doing it. I'm not sure if you can hack the wireless lan card do access the same channels or not. They sell the WRT54G domestically and internationally. The chipsets can handle all the channels, but the firmware limits the US version to 1 - 11.

      --
      Retail Retreat

    11. Re:overlap? by wankledot · · Score: 2, Interesting

      Yes, except with wireless there are no solid boundries, so it's not completely the same. You could have 6 non-overlapping channels are still have interfearance problems if they are stepping over each other. . It's very possible to have overlapping pieces, but as long as you manage your power levels and design it well, you should be OK.

      --
      My sig is blank, I typed this by hand.
    12. Re:overlap? by tcgroat · · Score: 2, Insightful

      This channel-hogging system is just as bad as using high-power amplifiers to blow other users off the channel. "My system is the only one that counts. I won't share with anybody else." It takes many times its fair share of a limited resource, ignoring a deliberate design strategy to use limited power (range) and reduced bandwidth. That design strategy exists to enable cooperative sharing of the available spectrum. The parallels to the me-first hooliganism on 27MHz Citizen's Band are frightening. Without cooperation and compliance to established standards and regulations, the range and through-put arms race will make wireless LANs useless to everyone.

    13. Re:overlap? by pimpin+apollo · · Score: 3, Informative

      Maybe I'm missing what you're getting at, but the 802.11b definitions for channels aren't used by anything else, but the spectrums that they cover are still unregulated... which means that anything can use it.

      Now if you're saying that you can't see those with a 802.11 aware device then yeah, but if I made some device that just broadcast randomness on the 2.4-2.5ghz range then that would interfere with all of those channels. It's also interesting to note that these ranges differ depending on the country. Japan's different than US/Canada.

      The full ranges are in the kismet documentation if I remember correctly.
      But the overlap is because the upper freqency for channel 1 is 2.423 while the lowest end for channel 6 is 2.426. 5 ranges from 2.421 to 2.443.

      Still, the FCC doesn't have any say over what those channel mappings are; meaning that a cordless phone could easily interfere with those channels (and does).

  31. More throughput... but... by kneecarrot · · Score: 2, Insightful

    More throughput but more pesky interference with phones and whatnot.

    --

    I always save my last mod point to mod up a good troll. You people are too serious.

  32. Tragedy of the commons forming! by LostCluster · · Score: 4, Insightful

    Of course, if you use the entire 2.4 GHz band, your neighbor can't. That's part of the reason why we have multiple channels to keep everybody from running into each other time. I highly doubt this group has bothered to test what kind of downside there is for a standard-issue WiFi setup operating 100 yards away.

    1. Re:Tragedy of the commons forming! by MrBlue+VT · · Score: 5, Informative

      I live right next to a university and I can see at least 15 different access points on any given day from my wireless link. I use it for internet access to the university and I can definatly tell when my neighbors are using their own LAN cause it causes a lot of packet drop outs. Not to mention about half of those APs have "linksys" as their SSID with no WEP enabled.

      It gets better during the summer when a lot of the students around me leave and shut off their APs.

    2. Re:Tragedy of the commons forming! by bbdd · · Score: 2, Interesting

      mod up the parent. this is a big problem.

      i live in a tightly populated suburban area and i can see 8 or 10 APs immeditately around my home using simple tools like netstumbler. this doesn't count APs that don't announce their SSID, as well as who-knows-how-many 2.4ghz cordless phones.

      my 2.4ghz cordless phones get interference all the time from what i can only assume are everyone elses APs and phones around me.

      simultaneous multiple channel use is a bad idea, unless you are out-of-range of others...

    3. Re:Tragedy of the commons forming! by WolfWithoutAClause · · Score: 2, Informative
      14 dBi isn't very sensitive- it's only about a 10x gain. That means that approximately someone 3x closer to the AP will swamp you out.

      For directionality to work, it requires widely spaced antennas (many meters), and this allows far more discrimination than your aerial.

      --

      -WolfWithoutAClause

      "Gravity is only a theory, not a fact!"
    4. Re:Tragedy of the commons forming! by Anonymous Coward · · Score: 5, Insightful

      Just log in to their default-passworded APs and set them to use channel 1. Then set yours to use channel 6. Let them deal with packet loss.

  33. Overlap explained by phreak03 · · Score: 4, Informative

    Any connection uses actually, the three channels around it for the connection anyways,
    if you've ever tried actually haveing 11 acess points on different channels you'll notice massive interfearence

    --
    come comment on the madness at http://slashdot.org/~phreak03/journal/
    1. Re:Overlap explained by jdhutchins · · Score: 2, Informative

      A connection, by default, only uses one channel. However, it spills into adjacent channels because of the quality of the transmitter and the fact that the channels are fairly close together and narrow.

  34. As if Wi-Fi space wasn't crowded enough already... by misleb · · Score: 3, Insightful
    I've been in places where you can't find a free channel because there are too many other people using Wi-Fi in the area. Now we're going to have individuals using ALL of the non-overlapping frequencies? That really sucks. As far as I am concerned, Wi-Fi as we know it will not go very far. There is just no way people are going to be able to share such a limited frequency spectrum... not in densly populated areas, anyway. I'll take good ol' reliable wires any day. Wireless is overrated.

    -matthew

    --
    "THERE IS NO JUSTICE, THERE IS ONLY ME." -Death
  35. no trimode? by MoFoQ · · Score: 2, Interesting

    no 'g'?

    but it's a good idea.
    Hopefully, other chipset makers (TI, etc.) follow suit, which in turn will reduce costs (thx to competition).

    Of course, if it can do all three, 'b', 'a', 'g' separately, and each with the parallel-ness, that would kick ass.

  36. Interference by Ctrl-Z · · Score: 3, Insightful

    This type of idea is not new, and I have seen it in wireless routers/nics for months. The primary drawback is that if you are using up all those channels, your neighbour's wireless network won't have anywhere to go. Conversely, if you are that neighbour, it wouldn't make you very happy.

    I consciously decided against buying something like this for that very reason when I bought my wireless hardware, even though the cost difference was negligible.

    --
    www.timcoleman.com is a total waste of your time. Never go there.
  37. Yeah! Screw the neighbors! by Anonymous Coward · · Score: 3, Funny

    Take up all the channels, get a stronger transmitter, and knock their wireless out!

    1. Re:Yeah! Screw the neighbors! by Peeet · · Score: 2, Funny

      Ha, if any of my neighbors did this, I would just be happy that my free internet was finally increasing in bandwidth and signal power.

  38. Re:Frequency band to be reorganized? by Devil's+BSD · · Score: 2, Informative

    802.11 is the IEEE standard, and the 'b' section of that pertains to a wireless network capable of 11 MBps (the 11 in 802.11b has nothing to do with the 11Mbps theoretical throughput, just a coincidence.) In reality, 802.11a, b, and g operate in the 2.4 GHz range, like the 2.4GHz cordless phones.

    --
    I'm the Devil the Windows users warned you about.
  39. Re:Firmware by The+Clockwork+Troll · · Score: 2, Interesting
    The immediate benefit to legacy clients is that they can be partitioned into 3 channel groups, each with its own full allotment of 802.11g bandwidth.

    You would only need a hardware upgrade if you wanted each client to be able to make use of multiple channels simultaneously and reach that 50Mbps throughput figure quoted in the article.

    Otherwise it's a solution for reducing bandwidth contention in heavily trafficked networks (and protecting 802.11g users from bandwidth degradation by 802.11b clients, as mentioned).

    --

    There are no karma whores, only moderation johns
  40. Re:As if Wi-Fi space wasn't crowded enough already by thrillseeker · · Score: 5, Funny
    I'll take good ol' reliable wires any day. Wireless is overrated.

    Well, it's kinda handy when you don't want any, ah, wires.

  41. Re:Use Multiple Channels by Anonymous Coward · · Score: 2, Insightful

    Yeah, instead of driving a long vehicle with multiple rows, everyone could be in the front seat! Too bad if it makes it difficult for others to change lanes or bypass problems.

  42. Re:What about 802.11G? by fidget42 · · Score: 3, Informative
    If it works for that it'd be well cool and would give speeds close to a wired network...
    Actually, no. A wired network provides a dedicated connection, while a wireless provides a shared one. This is basically the difference between 10baseT and 10base2. The shared connection (wireless and base2) will have to deal with collissions and will yield about 20-30% max load (depending on the kind of traffic). This is why your G network will only yield 11Mbps and not the full 54Mbps. Your 100baseT network will blow away anything wireless, unless you want to go with a dedicated wireless link (and then, um, why is it wireless?).
    --
    The dogcow says "Moof!"
  43. Fah. Not worth it. by Slayk · · Score: 2, Redundant

    As if setting up a wireless network in an apartment wasn't a big enough pain in the ass already, now I've got to worry about the yokel next door hogging all the available channels?

    This is going to casue more problems in resedential areas than it will solve.

  44. Valid Uses by yoshi_mon · · Score: 2, Insightful

    While it's been duely noted that using up more channels could interfere with others who are trying to use 2.4, there are a number of applications I can see that would be useful for this type of setup.

    Large old office buildings that arn't wired for ethernet, large warehouses, and people who live on large plots of land.

    Yes, if you are living in a typical burb or in the city and try to use one of these you could run into issues with running out of channels. However not everyone lives/works in small areas.

    --

    Really, I know what I'm doing...Ohhhh, look at the shiny buttons!
    1. Re:Valid Uses by LostCluster · · Score: 2, Interesting

      Large old office buildings that arn't wired for ethernet, large warehouses, and people who live on large plots of land.

      Common bond: Areas where for the range of WiFi, you control nearlly all of the territory. Therefore, you're sure you're not getting in the way of anybody else because there's nobody else arround.

      A densely packed dorm or appartment house is not the place to do that. It's to the point that in 2-family dwellings, the families need to agree on a consumer bandwidth sharing plan between each other so they don't buy devices that'll collide. Something like "You go on channel 3, I'll go on channel 10 for WiFi, and we'll reserve 900MHz for phones so don't get a 2.4GHz one..."

  45. Re:As if Wi-Fi space wasn't crowded enough already by LostCluster · · Score: 2, Insightful

    Yep... but you have to be careful what you're using is right for your application. If you're using WiFi to go accross the room, you should be using Bluetooth.

  46. Sounds like by ajs318 · · Score: 2, Insightful

    This just sounds like a new form of bogarting to me. The whole idea of there ever being multiple channels in the first place was so that everybody would have a chance of finding a free one -- things like this go right against that idea.

    If it isn't actually illegal, it's certainly anti-social. But then again, I don't use any wireless kit anyway ..... I need to have a power cable, so I don't mind having a network cable as well.

    --
    Je fume. Tu fumes. Nous fûmes!
    1. Re:Sounds like by quantum+bit · · Score: 3, Interesting

      It's not illegal by the FCC because anything goes in 2.4 GHz so long as you don't go over the power limits... there's no bandwidth-footprint limit that keeps you from using everything between the lines.

      So if my neighbors get one of these I just need something that will broadcast random noise at the maximum allowable power level over the whole 2.4Ghz band, with a directional antenna. Then we'll see how long it takes for them to give up and take it back to the store because it doesn't work.

  47. What they are really talking about by ZPO · · Score: 5, Informative

    Based on reading the article they are talking about a software defined radio (SDR) which is capable of operating discrete carriers and user communities on each of the 3 non-overlapping channels. They are not talking about bonding all 3 channels into a single data link.

    Based on the article the chipset will be *capable* of using all 3 non-overlapping 2.4Ghz ISM channels. That will allow the associated users to be split across the 3 channels rather than all on a single channel and competing for access to the channel.

    The same tradeoffs that drive WLAN design today will still exist. Its not a panacea, but it does add new possibilities to the engineer's set of available solutions.

    By opening up the front end of the radio they can look at the whole band and do some very interesting noise reduction techniques. This is alluded to in the article, but I think its the most promising part of the chipset. The ability to identify and reduce the affects of wideband noise will got a long way to improving reception of WLAN signals....

  48. tradeoff by l33t-gu3lph1t3 · · Score: 2, Interesting

    While combining channels may be a somewhat decent idea, it has a serious drawback: you lose your usable channels! I believe that maximum feasible number of users on any one access point is about 50, right? That's on channels 1,6,11. Sure you get more speed by using just one channel and sharing the resources of all 3, but hell, now only about 17 people can use the network!

    --
    ------- "From bored to fanboy in 3.8 asian girls" ----------
    1. Re:tradeoff by wankledot · · Score: 2, Insightful
      50 is a great number to design around, because any more than that you will be cut down to a trickle of bandwidth for each one. The access points technically support quite a few more simultanous connections than that, but no one is going to suggest that you design a newwork for a thousand clients per AP. There might be some odd situation where you need more than a hundred clients per AP for some low-bandwidth use (can't think of one, maybe like, a zillion iPaqs in a big room with one AP.. who knows.

      IOW, you could have a lot more than 50, but you really shouldn't.

      --
      My sig is blank, I typed this by hand.
  49. I can see the FCC loving this. by Halvard · · Score: 2, Interesting

    The licence that 802.11, A, B, G, etc. falls under says that if you inferfere (and you are discovered to be the culprit), you can't use it. I'm paraphrasing but I suspect that if you saturate the bandwidth available in the frequency and you get outed, then you'd have to stop using at least all the frequencies or the offending radios.

  50. Dlink has a similar idea by FigWig · · Score: 3, Interesting

    Dlink's AirExtreme G products advertise speeds up to 108 Mbps. Their literature implies that they use two wireless channels to achieve this speed.

    I have their wireless card & router, but can't get the 108 speed because of some legacy b adapters in the network. The G speeds are quite nice - even though 802.11b's theoretical speed is higher than my DSL bandwidth, it's actual performance was quite dissapointing.

    --
    Scuttlemonkey is a troll
  51. Overlap affects B and G, Not A or H by Erik_ · · Score: 2, Informative

    The 2.4Ghz bandwidth used by 802.11b and 802.11g have overlaps. The 5Ghz used by 802.11a and upcoming 802.11h (802.11a with Power Management) have non overlapping channels.

    802.11g => ~32Mbps throughtput x 3 non-overlapping channels = ~90Mbps total usable bandwidth
    802.11a => ~25Mbps throughput x 12 non-overlapping channels = ~300Mbps total usable bandwidth
    802.11h => ~25Mbps throughput x 24 non-overlapping channels (due to better pwr mgmt) = ~600Mbps total usable bandwidth

  52. Not quite. by jvonk · · Score: 5, Informative
    A connection is centered on a channel. If you remember your basic signals class, the bandwidth of the connection is dependent upon the width of the signal. Therefore, the actual bandwidth (in the RF sense) consumed by a connection is dependent upon the bandwidth (in the networking sense) of the link. Nyquist theorem means that an 11 Mbps link consumes a nominal 22 MHz (11 MHz on either side of the 'center' frequency, aka. 'channel')

    You can read this for a little more info.

  53. Re:As if Wi-Fi space wasn't crowded enough already by System.out.println() · · Score: 2, Informative

    Unless of course, you want a faster speed. By my understanding Bluetooth is about 1/10 the speed of wifi (unless I heard wrong.) And that's just 802.11b, not g.

  54. Re:As if Wi-Fi space wasn't crowded enough already by Gyorg_Lavode · · Score: 2, Funny
    Well gee, I guess I could just run out and buy that bluetooth AP, bluetooth pcmcia card, and blue tooth bridge (well, 2 devices of course), to replace the wireless stuff I have in my apartment.

    Except that .11 is cheap and easy to get/ impliment while bluetooth is almost nonexistant.

    --
    I do security
  55. Re:What about 802.11G? by TheCrazyFinn · · Score: 2, Informative

    Incorrect. 802.11g's practical max throughput is around 25Mbps (Half of theoretical max) and even if all of your clients are running .11g cards, you have a shared bandwidth topology. Given the same restraints, the almost 100% bandwidth advantage of 100baseTX will show.

    In fact a switched 10baseT network will perform about as well as an 802.11g network, and possibly better if you can run all of your systems in Full-Duplex mode (Not a given for 10baseT hardware)

    --
    "You've got an invalid haircut" -Warren Zevon - Life'll Kill Ya
  56. Re:What about 802.11G? by TheCrazyFinn · · Score: 2, Informative

    That's a switched network, not a 'dedicated' one. Yes, the RF channel is a 'dumb hub' but many 100baseTX implementations are also 'dumb hubs'. 100baseTX Switches are ubitquous now, but that's only happened in the last couple of years, and many large networks are still hub based due to cost reasons.

    --
    "You've got an invalid haircut" -Warren Zevon - Life'll Kill Ya
  57. same effect using two wifi cards? by stiller · · Score: 3, Interesting

    Maybe I'm missing something, but could you not achieve the same effect by whacking in two wifi cards and using some loadbalancing scheme in software? I don't see why this would be any slower than a hardware implemented solution, I think the CPU cycles spent are hardly the bottleneck here. Having said that, I think this is a silly solution that only wrecks the whole shared spectrum idea of wifi. If I were a wlan network admin, I would find (packet analyze) and block these guys. (not applicable on public networks ofcourse).

  58. Re:What about 802.11G? by timeOday · · Score: 3, Insightful
    If I understand correctly, you're saying 10base2 is shared while 10baseT is not? That's not true. Both wire types are used for ethernet, and both are shared. Ether way, collisions aren't that big a deal after all, see the classic reference:
    Ethernet works in practice, but allegedly not in theory: some people have sufficiently misunderstood the existing studies of Ethernet performance so as to create a surprisingly resilient mythology. One myth is that an Ethernet is saturated at an offered load of 37%; this is an incorrect reading of the theoretical studies, and is easily disproved in practice. This paper is an attempt to dispel such myths.

    ...

    Figure 10 shows excess delay , a direct measure of inefficiency. It is derived from the delays plotted in figure 8. The ideal time to send one packet and wait for each other host to send one packet is subtracted from the measured time. The time that remains was lost participating in collisions. Notice that it increases linearly with increasing number of hosts (offered load). When 24 hosts each send 1536-byte packets, it takes about 31 milliseconds for each host to send one packet. Theoretically it should take about 30 mSec; the other 1 mSec (about 3%) is collision overhead. Figure 4 agrees, showing a measured efficiency of about 97% for 1536-byte packets and 24 hosts.

    The upshot is that ethernet can carry very close to its rated capacity even if there are a lot of hosts and a lot of collisions. (Of course nowadays we tend to use switches instead of hubs anyhow, but that's not a at all inherent in 10baseT wiring).

    Whether wireless will work quite this well, I don't know.

  59. scanning networks by Gyorg_Lavode · · Score: 3, Interesting

    Would a card like this, integrated with airsnort and appropriate drivers allow quicker characterization of the network traffic in an area?

    --
    I do security
  60. Re:What about 802.11G? by 42forty-two42 · · Score: 2, Insightful
    Oh, and 1000baseTX is a switched-only Ethernet(Of course, it's only really ethernet due to marketing decisions).
    Actually, it's called "ethernet" because its frame format is identical to that of the slower variants, and it supports autonegotiation to be backwards-compatible with 10Base-T and 100Base-TX.
  61. Misunderstanding of Engim by arrianus · · Score: 5, Informative

    What Engim is doing is actually a good bit more sophisticated than any of the Slashdot posts imply. When you transmit, you usually have two types of bandwidth: how much bandwidth you are using, and how much you are interfering with. For instance, a simple AM broadcast will require maybe 8KHz of the spectrum on which it actually transmits data. Since transmitters are imperfect, however, it may actually interfer with transmitters on, say, 20KHz of spectrum.

    As a result, if you're in a big company, and set up 3 off-the-shelf 802.11b access points, on 3 different theoretically non-overlapping bands, you'll still get something on the order of, maybe, 1.6x the bandwidth you'd get with one.

    What Engim does is it has an insanely fast ADC/DAC front-end, that grabs the entire 802.11b/g spectrum, including all the bands. Then, they have a fancy DSP that looks at the bands together, figures out how they interfere with each other, and sorts them out. As a result, in a theoretical world, where only notebooks were transmitting to the access point, they would have 3x the bandwidth. They do fancy transmitting techniques, so that notebooks on all 3 bands can hear at the same time. So if the wireless access point was transmitting, and all the notebooks receiving, they would, again, have 3x the bandwidth.

    The problem is that notebooks don't have this sort of technology, so when they transmit, they cause interference for other notebooks. If the Engim WAP transmits on band 1 to notebook A, and notebook B transmits on band 2 at the same time, the transmission from notebook B may interfere with that from the WAP. As a result, in practice, it's a little less than 3x the bandwidth, but not a heck of a lot less. They try to juggle notebooks between bands, based on location, so this doesn't happen, but it doesn't really work too well.

    The technology they have is wicked cool, actually. For those worrying about interference -- it's really not a problem. First of all, this isn't for personal WAPs, but for $1000 access points you'd see on an IBM or Microsoft campus. They won't be going in apartments any time soon. You need a minimum of 3 very expensive chips for a single WAP (RF front-end, ADC/DAC, and DSP). Those places don't tolorate employees setting up their own WAPs anyways.

    Second, you still have the remaining bands. The way 802.11 works, with the interference issues described above, if I set up a WAP, and my neighbor sets up a WAP, we will be interfering. We'll both have wireless networks, but both with reduced bandwidth. You can still set up your own WAP on any of the remaining bands, and it'll work -- it's just that if you try to send a packet at the same moment as the Engim network, you'll get a collision and retransmit. This is what happens anyways. 802.11 was never designed to have many, non-interfering bands. It was designed to have many, interfering, overlapping networks, with packet collisions. By design, the total bandwidth of 5 overlapping networks, in the same area, is the same as if there was only one. Each network gets 1/5 of the bandwidth then. This is the exact issue Engim technology is meant to address.

    In terms of cell phones, etc. my impression is that the Engim technology was actually smart enough to look for "interference sources" and try to pick bands around them. This last bit is from an Engim PowerPoint slide, so I'm not sure if it's actually implemented or vaporware.

  62. Noooooooooo! by Jahf · · Score: 4, Insightful

    This will destroy wireless ISP communities.

    I already have only -2- channels that I can reliably use in my house without interference. Every other channel is in use for ISP access in our community or gets interference from cordless phones and microwaves.

    If you want more throughput, use different frequencies. Even if they are close to 802.11b/g that is better than going into the already established spectrum.

    Yes, I know that this is not mandated or regulated space, so there is not much I can do to enforce my needs. However unregulated waves only work if people make an effort to play well together.

    --
    It is more productive to voice thoughtful opinions (reply) than to judge (moderate) others.
  63. Re:Some comparrisons regarding G by bru_master · · Score: 5, Interesting

    This is good info to have, Keep in mind if you are trying to impliment wireless in a corporate environment, crappy range is a good thing. I have common problems with Cisco and Symbol AP's having such good range that too many users will pick up the signal in the cube farms of todays corporate america.

    I try to place my AP's so that 25 users will access them from there desks or conference room. Some conference rooms that are very large I will place 2 or 3 AP's on different channels with the power turned all of the way down so it will balance the user load between the them.

    Since there are only 3 non overlaping channels it is often a chore to design wireless in a room where the same channels dont overlap with each other. Poor range solves this problem. Think of how to put 5 AP's in a room with 3 channels, it can be done, poor range is the key.

    We urge our users to use their wired connection and use their wireless when in meetings or on the road at other corporate offices.

  64. Re:ummmm. by tonywong · · Score: 2, Funny

    They did. It's called the Excursion.

  65. Re:Department by BandwidthHog · · Score: 2, Interesting

    Holy shit people, who did I piss off with that inane comment to earn two Overrated mods? I mean, c'mon, some doofus actually burned a mod point on a comment already at 0? Wow. Must be the sig.

    --

    Quantum materiae materietur marmota monax si marmota monax materiam possit materiari?
  66. Quite not quite by rfmobile · · Score: 3, Informative

    Your nyquist analogy assumes a simple binary symbol set (ie. "1" and "0"). The signal bandwidth is a function of the symbol rate. If your symbol set is larger than just two symbols (say 8, or 16, or ...), then you can deliver more bits per symbol. That's why "G" delivers more data bandwidth than "B" in the confines of the same channel signal bandwidth.

    -rick
  67. Re:Some comparrisons regarding G by rfmobile · · Score: 2, Insightful
    I will place 2 or 3 AP's on different channels with the power turned all of the way down so it will balance the user load between the them.

    This is a great example of an intelligent use of the 802.11X protocols. Use only as much power as you need, and only where needed. As opposed to the usual (and wrong) tactic of using full-power in an attempt to squash a neighboring access point's signal.

    -rick
  68. Re:Some comparrisons regarding G by rsmith-mac · · Score: 2, Informative

    There are some inaccuracies I'd like to point out, if you don't mind:

    Somewhere I also read that Linksys will not support any turbo modes in their AP/Routers
    Linksys is supporting a "turbo" mode, thanks to Broadcom's "Afterburner" technology, which is implemented as Linksys's "SpeedBooster" technology. Afterburner requires a new revision of Broadcom's 802.11g chipset, however, so previous G products can't be enhanced, only new products.

    Atheros already had 108mb/s A support in turbo, allowing 45mb/sec throughput by using multiple channels
    Atheros and Broadcom are taking 2 different approaches to "turbo" here; while SuperG uses multiple channels(and is proven to degrade other networks, albeit mostly Broadcom's, oddly enough) along with compression and other effeciency boosting technologies, Broadcom's Afterburner will not be using any sort of channel bonding, just effeciency boosting. This is an important distinction, since Atheros' implementation will be faster(more raw physical bandwidth), but Broadcom's implementation will be a "good neighbor" to other devices. Of course, if you even have to deal with other devices, you're screwed anyhow; just having a B device in the same sphere will require G devices to slow down to warn the B device, so all your fancy effeciency boosting tricks also get disabled.

    Anyhow, check out Tom's Networking's review of Linksys's WRT54GS router; it is loaded with information on SuperG, Afterburner, incompatibilities, and performance.

  69. Re:Department by BandwidthHog · · Score: 2, Insightful

    Well, the post was the post, the sig is just a sig. But if you'd like I'll gladly explain it. It is meant to remind people that you shouldn't do things that adversely impact the lives of others based on your superstitions. At least that's my take on it, I didn't come up with it (although I wish I had).

    --

    Quantum materiae materietur marmota monax si marmota monax materiam possit materiari?